Content Delivery Network or Content Distribution Network (CDN) is a large distributed System of servers deployed in multiple data centers across the world. OR
CDN is a complex collection of Edge Servers and DNS Servers .( collection of edge servers is called a <PoP> Point of Presence or a Location). Edge server generally used large amount of the SSD drives. Edge servers cache your content on their ultra fast SSD drives and deliver it through the most robust networks of the Internet to End-user
The ultimate goal of a CDN is to serve content to end-users with high speed ,availability and high performance.
When your End-user requests content on your CDN, DNS servers redirect your End-user to one of the nearest edge servers which is close to the End-user. The redirection algorithm redirects your End-user to the edge server which has the best latency (lowest ping) to your end-user. This not only eliminates the distance that content travels, but also reduces the number of hope a data packet must make. The result is less packet loss, optimized bandwidth and faster performance which minimizes time-outs.